:Product: 20010329RSGA.txt :Issued: 2001 Mar 29 2200 UTC # Prepared jointly by the U.S. Dept. of Commerce, NOAA, # Space Environment Center and the U.S. Air Force. # Joint USAF/NOAA Report of Solar and Geophysical Activity SDF Number 088 Issued at 2200Z on 29 Mar 2001 IA. Analysis of Solar Active Regions and Activity from 28/2100Z to 29/2100Z: Solar activity was high. Region 9393 (N17W18) produced an X1/1N event at 29/1015Z. This event had an associated Type IV radio sweep, a tenflare of 4700 sfu, and a full halo CME was reported from LASCO/SOHO imagery. This earth-directed CME occurred at approximately 29/1030Z. Region 9393 also produced numerous minor M-class events during the period. Region 9393 has shown slight growth in area since yesterday and is currently over 2400 millionths in white light. No new regions were numbered today. IB. Solar Activity Forecast: Solar activity is expected to be high. Region 9393 still has the best potential to produce a major flare. IIA. Geophysical Activity Summary 28/2100Z to 29/2100Z: The geomagnetic field was quiet to minor storm. The greater than 10 MeV protons crossed the 10 pfu event threshold at 29/1635Z and has not yet peaked (highest flux observed so far was 18 pfu at 29/2050Z). IIB. Geophysical Activity Forecast: The geomagnetic field is expected to increase during the first day of the period to active to major storms levels due to a CME passage. The passage of a faster CME, from the X1 event today, may occur later on the first day. With the passage of the second CME, conditions are expected to be at active to major storm levels with isolated severe conditions possible. During the last half of the period, conditions are expected to decrease to unsettled to active conditions. CME passage could increase the strength and duration of the 10 MeV proton event currently in progress. Another proton event is possible, and likely stronger, if Region 9393 produces another major flare as it transits the solar western hemisphere. III. Event Probabilities 30 Mar-01 Apr Class M 80/80/80 Class X 30/30/30 Proton 99/30/30 PCAF yellow IV. Penticton 10.7 cm Flux Observed 29 Mar 262 Predicted 30 Mar-01 Apr 260/255/250 90 Day Mean 29 Mar 163 V. Geomagnetic A Indices Observed Afr/Ap 28 Mar 019/031 Estimated Afr/Ap 29 Mar 020/025 Predicted Afr/Ap 30 Mar-01 Apr 045/050-045/050-025/030 VI. Geomagnetic Activity Probabilities 30 Mar-01 Apr A. Middle Latitudes Active 30/20/40 Minor storm 40/50/30 Major-severe storm 20/25/15 B. High Latitudes Active 20/10/30 Minor storm 40/40/40 Major-severe storm 30/40/20